The evolution and development of limb regeneration: a perspective from studies on the red flour beetle, Tribolium castaneum. Yuichiro Suzuki. Department of Biological Sciences, Wellesley College, Wellesley, MA.

   Many, if not all, metazoans have the ability to regenerate parts of their bodies. Despite the independent evolution of appendages in the protostome and deuterostome lineages, many species in both of these groups are capable of regenerating. To compare the mechanisms underlying limb regeneration across metazoans, the genetic regulation underlying larval leg regeneration was investigated in the red flour beetle, Tribolium castaneum. Knockdowns of several key factors known to be involved in the early stages of vertebrate limb regeneration also affected wound healing and blastema growth in Tribolium. In contrast, the re-patterning of limbs was found to involve a reversion to the embryonic mode of appendage patterning. Because vertebrate and insect limbs are patterned differently during embryogenesis, the mechanisms underlying re-patterning differ between vertebrates and insects. These findings suggest that studies on the earliest stages of regeneration may shed light on the cellular mechanisms common to regeneration across all metazoans.